I use only one logbook for each boat. It has areas on the second page to write observations, notes, maintenance reminders, etc.
I track slightly more than probably the next guy, but I use spaces for all my navigation, inboard or outboard run time (I also have hobbs meters), weather observations, forecasts, barometer, fuel used/ taken on, water used / taken on, parts or spares used and locations, repairs made or needed to be made, groceries bought, used, and even meals prepared and propane used / tanks replaced. Heck I even keep people's names and boat they are on when I meet them and log fun things like the rafting up or anchoring together for cocktails, as well as guests and so forth.
I've digressed. I love my logbook. It makes for a good read later on. Back to the maintenance; I have a big three-ring book/binder that I keep all of my instruction manuals, part numbers torn from box tops, regular writing paper with drawings about wiring diagrams, repairs made, and anything else I've done that I need to keep notes about. Receipts stay at home in the safe.
The logbook simply records when I made a repair, and what I have on the "to-do" list with check boxes next to them. When I need to reference a paticular part number or data sheet, or even manual, I open the three ring binder with the plastic page protectors in them holding all the loose pages. It makes it easy for me having a to-do list in the log and the technical library and parts list elsewhere.
(Sorry for any typos, my wireless keyboard batteries are dying and keys are not typing well)